End of the tongue, we're told (6)
I believe the answer is:
finish
'end' is the definition.
(finishing is a kind of ending)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for finish that I've seen before include "Terminate, conclude" , "Conclude, end" , "perfection" , "Bring to an close" , "Pefect" .)